Electrical alarm system



July 14, 1959 c. R. WATTS 2,895,125

ELECTRICAL ALARM SYSTEM Filed Dec. 9, 1954 3 Sheets-Sheet 1 54 Do m I 40 I4- LL68 L Lwae 44' 2 FR! :2 PR2 36 PR3 36 a4 6 t 30 4e 4a LI I 46 48 $48! '12; 52753 FIR548 l0 2 42 2e 22 I @L 20% A E P2R2 RI 4s '30 46 50 q -H F2Rl 32 F2 /46 FIG. I

INVENTOR. CLA ENCE R. WATTS ATTORHIY y 1959 c. R. WATTS 2,895,125

ELECTRICAL ALARM SYSTEM Filed Dec. 9, 1954 3 Sheets-Sheet 2 FIGS INVENTOR. CL ENCE R. WATTS mm. W

July 14, 1959 c. R. WATTS 2,895,125

ELECTRICAL ALARM SYSTEM Filed Dec. 9. 1954 s sheets-sheet z FIG.

INVDVTOR. CLAR ENCE R. WATTS United States Patent ELECTRICAL ALARM SYSTEM Clarence R. Watts, Pedro Miguel, Canal Zone, assignor, by mesne assignments, to Patrick F. Henry Application December 9, 1954, Serial No. 474,118 8 Claims. (Cl. 340-227) This invention relates to an electrical alarm system and particularly to a switch actuated system of this sort for automatically policing for abnormal condition in a building having a plurality of floors and a plurality of individual spaces considered separate on each floor.

Such a system as hereinafter disclosed is particularly useful as a fire alarm system in buildings which have several floors above the ground and many individual rooms on each floor. Obviously unless some constantly watching means is provided it is likely that sooner or later a fire will occur in one of the rooms on one of the floors and probably the fire will not be noticed until it has gained substantial headway. Such is particularly true in buildings where rooms are only intermittently occupied during day and night. Accordingly, gigantic loss of property can be avoided if the initial fire is brought immediately to the attention of the fire department as almost any fire can be readily controlled if caught in the beginning stages.

The present system is completely automatic with optional alarm indication and with, if desired, self-supervision of its own circuits in order to indicate also any breakdown of one of its elements or damage to any of the circuit wiring. As is customary in alarm systems the basic element is a switch located in each of the individual rooms and actuated solely upon the occurrence of some abnormal condition. For example, in the case of fire alarm system, the switch would be a thermostat circult closer operable upon the sudden rise or ultimate peak of heat to close a circuit. Since there would be at least one thermostat in each room, the number of thermostats would be the multiple of the number of rooms times the number of floors and as shown hereinafter the wiring between thermostats is done in multiple, hence the expression manifold."

Other systems are in existence using the manifold or multiple association of per se thermostats and therefore that specific portion of the system alone is not new. The present system is a new arrangement in a manifold and optionally as a combination with self-supervised alarm system. The term self-supervised refers to the system having means therein for automatically indicating trouble within the circuits or electrical elements.

An object of this invention is to provide an alarm system which is supervised in simple and expedient manner.

Another object of this invention is to present a system requiring a minimum of electrical elements such as wire and relays.

An additional object of this invention resides in the particular manner of locating supervisory control elements with respect to the circuits through the indicator means and through the circuit closer devices in the rooms.

The particular direction and location of the wiring with respect to a central indicator device and the various floors and rooms forms a feature of my invention.

One important object in this invention resides in the use of relays as supervisory control devices and in locat- 2,895,125, Patented July 14, 1959 ing and wiring these relays so that only as many relays as the maximum number of floors or rooms whichever the greater is necessary.

It is important also to note the advantage herein presented of having an arrangement in the alarm and locating system which permits the construction of a pre-fabricated control unit which is easily and dependably applied to any building regardless of the number of rooms and floors or the ratio and with no more than the removal of excess connections.

The present system is extremely desirable because of its flexibility in allowing the use or omission of additional alarm signals and auxiliary equipment depending upon the cost allotted in the purchaser's budget and in view of local fire code requirements.

After the disclosure of the present invention has proceeded sufficiently, other and further objects and advantages of the system will become apparent to those skilled in the art and the following description in detail is in conjunction with the accompanying drawings wherein like parts are designated by the same reference characters in the several figures in which:

Fig. 1 is an electrical diagram of a complete system for a two floor and three room building but without certain auxiliary elements.

Fig. 2 is an electrical diagram of the portion of thermostat switches and terminal strip in a system for a five floor, ten room building.

Fig. 3 is an electrical diagram of all of the circuits for the five floor, ten room building in Fig. 2 and duplicating the terminal strip and two thermostats of Fig. 2.

Fig. 4 is a purely diagrammatic view of the electrical system of Figs. 2 and 3 for the purpose of presenting this system in a diiferent manner.

Briefly described, the present system employs a source of current, a thermostatically operated circuit closer in each defined room of each floor in a building, a plurality of closed combined indicator and supervisory circuits connected across said source of current and each extending from one side of said source and connecting one side of all the thermostatically operated circuit closers on one fioor through a current limiting means with the other side of one of the room circuit closers and all the room circuit closers on all the floors of like location, supervisory indicating means operable upon substantial loss of current in any one of said closed indicator circuits, a floor alarm indicator for each of said floor circuits on one side of said respective current limiting means, and a room alarm for each of said room circuits and on the other side of the respective current limiting means, the closing of any thermostatically operated circuit closer causing increased current which is sufiicient to operate simultaneously a floor indicator and the room indicator corresponding to and on the other side of said circuit closer.

Proceeding to a more detailed description, the system in Fig. l rep-resents a simple and inexpensive installation in accordance with the present invention. The building to which the system is applied is of two separate floors with three separate rooms or compartments defined on each floor, substantially one on top of the other in corresponding rooms. Since the system shown is a fire system, a circuit closing device is provided in each one of the separate rooms on each floor. It is permissible to use any suitable thermostatically controlled circuit closer, hereinafter referred to simply as thermostat, but preferable that the type be used which operates by virtue of a sudden rise of temperature in addition to the normal operation through the reaching of a pre-set minimum temperature. Many suitable thermostats are available on the commercial market and some are found described in both US. patents to Griffith, Patent Numher 2,413,140, and to Van Houten, Patent Number 2,267,484.

For convenience and clarity, the thermostats are shown in plan view as if they were on the same level rather than in both plan and elevation which is the true representation of a building. In Fig. 1, each of the thermostats are identified according to the exact location thereof, as for example, FlRl refers to the thermostat in the number 1 room on the first floor, F2R1 is the number 1 room on floor 2, and so forth. The circuit for the system begins with a source of current which, as shown, may be a D.C. battery 14 or group of bat teries with the plus side 16 and the minus side 18. Plus side 16 leads from the battery 14 through the coil 20 of a relay 22 having armature point 24 and contact arm 26 in a circuit to be described. Side 16 continues on and connects to a bus bar 28 from which a number of closed indicator and supervisory circuits begin. One such circuit begins with line 30 passing through a signal light 32 which will represent a signal for floor 1 as identified by FRI. Circuit line 30 leads to the thermostats 10 and is connected with one side of all of the thermostats 10 located on floor 1, these being FlRl, F1R2, and FlR3. Circuit line 30 then leads to and connects with one side of one of the coils 34 of one of a group of relays 36 each having a contact arm 38 in association with a respective point 40, the arms 38 and points 40 being in a supervisory circuit to be described. Line 30 then leads from the other side of the relay coil 34 to and through the other side of thermostat in F1R1 and also to one side of all the thermostats in compartments of like location and number, in this case the number 1 rooms. Circuit 30 then connects to and through another signal light 42 representing compartments of like number which in this case is the room light. Room 1 light 42 is one of a group of room lights 42 further identified by their particular designator R1, R2, and so forth and all leading to a common bus bar 44 connected to the other side of the line source 18.

With this arrangement, the source 14 has a number of closed indicator and supervisory circuits, such as 30, connected thereacross, each of which leads through a floor light to all floor thermostats thence through a relay coil, then through one group of all rooms of like number, and finally back through a room light to the other side of the line. Since in the present system there are two floors and three rooms on each floor, there is required two floor signal lights and three room signal lights. The circuits through these lights could be described as loop circuits or bend circuits since in actuality in a building they go up through thermostats and bend back to the source. The second such circuit in the present system is 46 beginning at bus bar 28, through signal light F2, through one side of all thermostats 10 on floor 2, through another relay coil 36, further identified as PR2, through one side of all thermostats 10 of another group of rooms of like number, in this instance all the room 2's, and finally through signal light R2 back to bus bar 44 on side 18.

Through the particular arrangement in the present invention, only a partial but complete circuit is needed to serve the third and final group of rooms R3. Ahead of the relays 6 and after thermostats 10 on line 46 is a branch circuit 48 leading to the relay coil of 36, further identified as PR3, and from there to one side of all the thermostats in the remaining rooms of like number, namely R3s, thence through the R3 signal light to the bus bar 44. All the lights 32 and 42 are in a particular circuit across the source 14. The circuits 30, 46, 48 are closed circuits and therefore have some measure of current in them at all times. Since the lights 32, 42 are in series on these closed, energized circuits they would burn at all times were it not for the resistance of the relay coils 34 in the respective circuits limiting the current to less than required by the light 32, 42. Accordingly, the coils 34 serve this purpose of limiting current as well as providing supervision as will be discussed hereinafter. In line with this, the characteristics of coils 34 are selected with regard to the initial source 14 and the rating of the lights 32, 42, or vice versa.

In the operation of the system by fire, heat causes one of the thermostats 10 to close which will then connect the circuit at its terminals so as to short the respective relay 36 thereby permitting increased current to flow in the line which will be sufficient to light a room light in series with a floor light. For example, suppose a fire stalts in room 22. Thermostat 10-F2R2 in room 22 will close and increased current will flow in line 46 around relay 36-R2 causing the F2 light to light with the R2 light. For effective execution, the signal lights 32, 42 would be located in one frequented spot such as the main desk in a hotel. Since it is desirable to have audible notice of this as well as visual, a bell circuit is made by a line 50 from side 16 to relay point 24 at normally open relay arm 26 and line 50 continues through a bell 52 and then to the other side of the line 18. When the increased current flows through one of the indicator circuits it also increases current in coil 20 selected as requiring an amount not in the normal circuit enough to pull contact arm 26 to an amount sufficient to so do. Therefore, at the same time as the lights light, the bell 52 rings.

The foregoing arrangement is readily supervised.

This term supervision refers to providing some manner of being informed if the system is out of order. The most effective method is to have a loud hell or the like sound whenever any trouble develops in the system to this end the relays 36 control the movement of their respective arms 38 which will be held away from its contact 40 by the attraction from coil 34 as long as it is sufficiently energized. Of course, if the current into any of the coils 34 is interrupted the attraction on the arm 38 for that coil will be lost and the arm 38 will be forced through conventional relay spring bias arrangement (not shown) into contact with its contact 40. All the contacts 40 are carried by and connected to a wire 54 leading to one side of the source while the contact arms 38 are connected with another Wire 56 connected through an alarm bell 58 to the other side of the line 16. Thus when the current is terminated in any of the circuits, contacts 38, 40 close and alarm bell 58 will sound. Upon hearing the alarm bell, an attendant or service man can inspect the system in order to locate the fault. When the trouble is corrected the system is restored to normal.

The system is extremely desirable from economy standpoint in both fabrication and installation due in large manner to the novel way of locating and wiring in the relays 36. The necessary number of relays 36 is always equal to the maximum number of floors or rooms whichever is the greater. In the Fig. 1 system the maximum number of rooms (3) is greater than the maximum number of floors (2) and therefore the number of indicator and supervisory relays 36 is three. In a six floor, three room per floor building the number of relays 36 will be six. In some prior systems is found the less desirable situation where the number of supervisory relays must be the sum of floors and rooms which necessitates the use of more than the present invention thereby requiring more time to install and a larger investment. Furthermore, the wiring of the relay coils 34 is flexible in that if there are more floors than rooms or vice versa the excess number of relays 36 (determined by subtracting the smaller number from the larger) have their coils 34 grouped with each other in sets of 2 or more, as in the case of PR2 and PR3 in Fig. 1. If desired, PR3 could have been grouped with PR1 by connecting wire 48 onto wire 30 some place ahead of relay PR1 and after the last of the thermostats 10 for floor 1.

The system disclosed in Figs. 2 and 3 is basically the same as that of Fig. 1 but with certain additions and being expanded to handle a 5 floor, room installation and having the characteristic of being capable of expansion to handle a 10 floor, 10 room situation without changing the number of relays. While the system is broken into two parts for study, it is necessary to combine Fig. 2 with Fig. 3 in order to see the complete system since Fig. 2 is actually a continuation of Fig. 3 with the exception that the connecting strip is shown in both figures and two thermostats 10 are shown in Fig. 3 and in actuality there is only one such strip so in order to follow the entire circuit it is necessary to visualize the strip in Fig. 2 and the strip in Fig. 3 as one strip with the proper connections made.

Fig. 2 is a plan view of the thermostats 10 for a 5 floor 10 room building which are arranged such that the lowermost line of thermostats on the sheet are floor l and successive floors reading on up the sheet while the left hand thermostats are in rooms 1 and successive rooms on across the sheet to room 10 at the right hand border. Therefore if one starts at the lowermost, left-hand thermostate 10 it is labeled as FlRl, while two above that is F3R1, and four to the right is FIRS. The thermostats 10 are grouped in a multiple or manifold system including an insulated terminal strip 60 having many jacks or pairs of terminals 62, there being one for each floor and each room. The terminals 62 are further identified on the drawing by being marked as Floors" 1, 2, 3 and so on, and as Rooms 1, 2, 3 and so on. Terminal strip 60 would preferably form one portion of a control and indicator box (not shown) located at one place in the building where it is likely to be noticed. The manifold wiring eliminates separate circuits to each thermostat and is attained by running wires 64 from each of the floor terminal strip floor terminals 62 to one side of all the thermostatic switches for that particular floor and Wires 66 from each of the terminal strip room terminals 62 to one side of all the thermostatic switches for all those particular rooms of like number. For example, wire 64 begins at bottom terminal 62 for floor 5 extends up to one side of all the thermostats on floor 5 and thence back to the top terminal strip. Likewise, wire 66 begins at bottom room terminal for room 1, extends upwardly through one side of all the thermostatic switches 10 for all room 1 locations and thence back to the top terminal for room 1. As a result, only ten separate wires are handling 50 thermostats. In a building installation, this means that from a central station only 10 wires are run from the central station instead of the 100 found in a non-manifold system, and there are only ten sets of terminals 62 on the strip 60 which simplifies the construction.

The complete system in Fig. 3 is adapted by transformer 70 to receive incoming A.C. current 72 of the ordinary 110-115 volt supply and reduce same with outgoing line 74 from the seconary 76 and also with taps 78 on secondary 76 leading to the coil and armature 81 for emergency D.C. standby and through another line 79 for A.C. pilot light 80. A rectifier 82 receives incoming line 74 and converts same to D.C. current on outgoing lines 84, 85 leading to a pair of switch contacts 86, 88 near the coil 81. A second pair of switch contacts 90, 92 are opposed to a respective contact 86, 88 and are connected, respectively, to the opposite line sides 94, 96 from a battery set 98 which will supply the emergency standby D.C. current in the event of failure of the A.C. current. A pair of relay switch arms 100, 102 are positioned within contact distance of a respective opposed pair of opposed contacts 86, 90 and 88, 92. Arms 100, 102 are each connected to a respective opposite side of the line 104, 106 and each is spring biased normally held against the spring in contact with 86, 88 so that line 84 continues as line 104 and line 85 continues as line 106. The 106 side of the line leads to a relay coil 108 near switch arms 110, 112 and contact points 114,

116 in circuits described hereinafter. Line 106 connects to a bus bar 118 having a plurality of the floor signal lights connected thereto, each light being further identified as F1, F2 and so forth. Each floor light 120 has safety shunt resistor 119 so that the circuit is complete even when the light burns out.

Each floor light 120 has an independent circuit 121 therefrom which begins at the bus bar 118 and continues in the manner of the circuits 30, 46 of the embodiment of Fig. 1. Accordingly, the line 121 runs from bus bar 118 through light Fl thence to one of the number 1 floor position on terminal strip 60, thence through one side of all thermostats 10 on floor 1, thence back to the other number one floor terminal, thence to a relay coil 36-FR1, then from the other side of relay coil 36-FR1 to one of the R1 terminals on strip 60, then through one side of all the thermostats in all room 1 locations, then to the other R1 terminal, and finally through a room 1 signal light 123 to a common bus bar 124 for all room lights which bar 124 is connected to the other side of the line 104. All room lights 123 have shunt resistors 125. From one side of the line beginning at the floor lights 120 each circuit like 121 follows the same pattern as in the system of Fig. 1, passing through the current limiting coil 36 of a respective relay. Since there are more relays 36 with coils 34 than there are floor lights, each floor circuit leads to more than one relay as seen by line 121 having line 122 leading therefrom just ahead of relay FRI into relay FR2, thence to room 2 terminal, and so on to room 2 light. The present system is grouped in successive pairs but could be grouped in threes or more. This unique arrangement provides extreme flexibility in fabrication and installation.

The contacts 40 of relays 36 are connected to a common line 124 which leads to line side 104 while the switch arm side 38 of relays 36 are connected to a common line 126 through trouble indicator bell alarm 56 thence through a switch 128 to the other line side 106. Leading from D.C. line 94 is circuit 130 through an A.C. trouble buzzer 132 and a D.C. pilot light 134. Across from switch 128, a contact 136 leads through circuit 137 and thru a fire buzzer otf light 138 to switch arm 110. A circuit 140 extends from line side 104 to line 137 and through fire buzzer 52, through a resistor 142, to the switch contact 116. Switch arm 112 leads directly to line side 106 while switch contact 114 leads by wire 148 through a switch 150 and resistor 152 to the bus bar 118.

In the operation of the system of Figs. 2 and 3, the D.C. emergency standby is automatically put into action by and upon the failure of current in the A.C. secondary 76 which deenergizes coil 81 and lets contact arms 100, 102 close on contacts 90, 92 which throws lines 104, 106 with sides 94, 96 of D.C. standby from the batteries 98. To indicate this fact, A.C. trouble buzzer 132 can be silenced by opening switch 128. Of course, light 134 will go out and contacts 100, 102 will return the system to normal source from rectifier 82 once the A.C. trouble is corrected.

The operation of the indicator lights 120, 123 is the same as in the system of Fig. 1 occurring upon the closing of a thermostat 10 which shorts out one of the current limiting coils 34 of relays 36 allowing full current to flow through the circuit from floor light 120 across thermostat 10 and through a room light 123 with sufiicient rating to light these lights and also to actuate the relay 108 pulling in switch arms 110, 112 causing bell 52 to sound and which may be locked in through circuit 148 having switch 150 and resistor 152. Therefore, bell 52 will continue to ring until switch 150 is opened momentarily.

The supervisory operation of the system is the same as that of Fig. 1. If current is terminated through any one of the relays 36, as by a broken wire, that relay will permit one of the arms 38 to close on a contact 40 thereby closing the alarm circuit through 126 on one side and 124 on the other causing bell 156 to ring. Bell 156 is silenced through the movement of switch 128 which will light 138 to remind that the system is out of order until corrected and until all relays 36 are restored to normal open position.

The system diagrammed in Fig. 4 is identical with that of Figs. 2 and 3 and the purpose of this is merely to repeat the system in a ditferent form of electrical diagram so as to point out in another way the relationship between certain elements such as relay contacts 38, 40 and relay coils 34. Terminal strip 60 is applied with Fig. 2 in the same manner as was Fig. 3. This is more of a functional diagram since, for example, the relay arms and contacts 38, 40 are grouped a distance from the coils 34 whereas actually they are within magnetic attraction.

While above has been shown and described in detail and with specific circuits in drawings a system with and without extras, this is not to be construed as any sort of limitation on the scope of the invention involved herein as the same may be done in several different ways and various substitutions, eliminations, modifications, and alternations may be made within the purview of this invention. For thoughts and questions involving scope of coverage, equivalency, definition of invention, and so forth reference is hereby made to the appended claims with constructions relating thereto.

I claim:

1. In an alarm system for a building in which there are a plurality of floors and a plurality of rooms on each floor, a source of electrical current, a switch in each of the rooms closable upon the occurrence of a condition therein, floor signal means for each floor, a plurality of closed indicator circuits each beginning at one side of the source and passing through a floor signal means to one side of all switches for that floor and through a current limiting means, said current limiting means connected through the other side of one of the switches on that floor for a room of particular designation through a room signal means to the other side of the line, the other indicator circuits extending in like manner through other floor signalling means and other rooms like and different designation until all rooms are related across an open switch to their floor, the minimum required individual current limiting means being in number equal to the maximum number of floors or rooms whichever is the greater, each of said respective floor circuits and said room circuits being in circuit with at least one respective current limiting means, each of said current limiting means normally completing a portion of the circuit associated therewith, and a loss of normal current in any of said current limiting means being an indication of trouble in a circuit associated therewith, whereby an indication of trouble in any circuit may be determined from said current limiting means associated therewith.

2. In an alarm system for a building in which there are a plurality of floors and a plurality of rooms on each floor, a source of electrical current, a switch in each of the rooms closable upon the occurrence of a pre-determined condition not normally present therein, a plurality of floor indicator circuits each beginning at one side of said source and connecting one side of a plurality of switches on the same floor in series with one another, a plurality of relay coils, a plurality of room indicator circuits each beginning at the current source side opposite from the floor indicator circuits and connecting one side of a group of switches in like designated rooms on different floors in series with one another, each floor indicator circuit including a signal device, each room indicator circuit including a signal device, said number of relay coils being determined by subtracting the lesser of the floor or rooms from the greater thereof, the relay coils being arranged in circuit with both a floor circuit and a room circuit and where the total number of one of either floor circuits or room circuits exceeds the other the relays being grouped by incoming circuits on the lesser number side and with separate circuits from the greater side, said relay coils normally being energized with a normal amount, and a loss of normal amount in any relay coil results from trouble affecting the electrical energy in the circuit associated therewith, said loss of said energy from normal amount being an indication of trouble in that circuit portion, whereby improper function of the system itself may be detected.

3. The alarm system as claimed in claim 2, there being a normally open supervisory circuit closable through loss of current in a relay coil, and signalling means in said supervisory circuit.

4. In an alarm system for a building in which there are a plurality of floors and a plurality of rooms on each. floor, a source of electrical current, a switch in each of the rooms closable upon the occurrence of a condition not normally present therein, a plurality of floor indicator circuits each beginning at one side of said source and connecting one side of a plurality of the switches on the same floor in series with one another, a plurality of room indicator circuits each connecting the other sides of a group of switches in like designated rooms on different floors in series with one another, each floor indicator circuit including an electrical signalling means, each room indicator circuit including an electrical signalling means, current limiting means in each of said floor circuits and said room circuits, the minimum number of current limiting means required being the maximum number of floors or rooms whichever is the greater, said current limiting means normally being part of a closed circuit portion in its respective circuit portion when said system is in normal working order, each of said current limiting means receiving an amount of electrical energy in normal condition and having a change therein in the amount of energy in response to a break in the circuit portion associated therewith, and the current condition resulting from said change, said change in energy amount in any of said current limiting means upon detection providing an indication of trouble associated with that circuit portion, whereby trouble may be discovered by electrical inspection of said current limiting means.

5. In an alarm system for a building in which there are a plurality of floors and a plurality of rooms on each floor, a source of electrical current, a switch in each of the rooms closable upon the occurrence of a condition not normally present therein, a plurality of floor indicator circuits each beginning at one side of said source and. connecting one side of a plurality of the switches on the same floor in series with one another, a plurality of room indicator circuits each connecting the other sides of a group of switches in like designated rooms on difierent floors in series with one another, each floor indicator circuit including an electrical signalling means, each room indicator circuit including an electrical signalling means, current limiting means in each of said floor circuits and said room circuits, the minimum number of current limiting means required being the maximum number of floors or rooms whichever is the greater, said current limiting means in excess of the number of floors or rooms whichever is the lesser being grouped in incoming circuit from the number of lesser floors or rooms and being independent on the circuits of the other of said floors or rooms, said current limiting means normally being energized when said circuits are operating properly, there being a change in electrical energy in any of said current limiting means in response to a change of condition in the circuit portion associated respectively therewith which would occur when there is damage to the circuit portion, said current limiting means thereby providing an electrical detection of trouble whereby trouble may be detected from said current limiting means from any change in normal thereof.

6. In an alarm system for a building in which there are a plurality of floors and a plurality of rooms on each floor, a source of electrical current, a thermostat switch in each of the rooms closable upon the occurrence of a condition not normally present therein, a plurality of floor indicator circuits each beginning at one side of said source and connecting one side of a plurality of switches on the same floor in series with one another, a plurality of room indicator circuits each connectin the other sides of a group of switches in like designated rooms on different floors in series with one another, each floor indicator circuit including electrically operated signalling means, each room circuit including electrically operated signalling means, a plurality of relay coils, each floor circuit being connected through a relay coil to a room circuit, said relay coil normally limiting the current in said combined circuits to an amount insufficient to actuate either of said signalling means, there being at least as many relays as the maximum number of floors or rooms whichever is the greater, the excess number of relays determined by subtracting the lesser number of floors or rooms from the greater thereof being grouped and connected on one side and receiving therefrom more than one circuit from the same floor or room whichever is of the lesser number and connecting on the other side thereof to an individual circuit of one of the other of said floors or rooms, the closing of any one of said thermostats causing current to by-pass said relay coil and increased current to flow through one of said floor signalling means and one of said room signalling means, said relays being actuatable in response to a change of electrical energy condition therein providing a positive detection of trouble in the respective circuit associated therewith, whereby a detection of trouble may be determined from said relays.

7. The system in claim 6 having in addition a supervisory alarm means, in a normally open supervisory circuit across said source, said circuit being closable by and upon the loss of current in any one of said relays.

8. In an alarm system of the class described for a building in which there are a plurality of floors and a plurality of rooms on eaclh floor, a source of electrical current, a thermostat in each of the rooms closable upon the occurrence of a condition not normally present therein, a plurality of floor indicator circuits each beginning at one side of said source and extending therefrom in independent circuits and each connecting one side of a plurality of the thermostats on the same floor in series with one another, a plurality of room indicator circuits each extending from the other side of the source and connecting the other sides of a group of thermostats in like designated rooms on different floors in series with one another, each floor indicator circuit including electrically operated signalling means, each room circuit including electrically operated signalling means, a plurality of relay coils, each floor circuit being connected through a relay coil to one of the room circuits said relay coil normally limiting the current in said combined circuits to an amount insufficient to actuate either of said signalling means, there being at least as many relays as the maximum number of floors or rooms whichever is the greater, each relay being in its respective circuit after the last of all the group of thermostats of either a floor or room and before the first of the thermostats of the other thereof, the excess number of relays determined by subtracting the lesser number of floors or rooms from the greater thereof being grouped and connected on one side thereof and receiving therefrom more than one circuit from the same floor or room or whichever is the lesser number and connecting on the other side thereof to an individual circuit of one of the other of said floors or rooms, the closing of any one of said thermostats causing current to by-pass said relay coil and increased current to flow through one of said floor signailing means and one of said room signalling means, a normally open supervisory circuit across said source, a movable relay for each of said relay coils normally open at the open portion of said supervisory circuit, contact point at said open portion, and signalling means in said supervisory circuit, the loss of current in any of said relays causing said supervisory circuit to become closed thereby actuating said signalling means.

References Cited in the file of this patent UNITED STATES PATENTS 2,605,342 Spurling July 29, 1952 

